Add the tentative sqlite3_allocate_queryplan() API. (CVS 3228)

FossilOrigin-Name: 7a3e97f76b1f4f97a04f7c5a9daa400402b2ff25

5 files changed, 60 insertions, 23 deletions

diff --git a/src/sqlite.h.in b/src/sqlite.h.in
index 023c90fff..f21438038 100644
--- a/src/sqlite.h.in
+++ b/src/sqlite.h.in
@@ -12,7 +12,7 @@
 ** This header file defines the interface that the SQLite library
 ** presents to client programs.
 **
-** @(#) $Id: sqlite.h.in,v 1.172 2006/06/13 14:16:59 danielk1977 Exp $
+** @(#) $Id: sqlite.h.in,v 1.173 2006/06/13 15:00:55 danielk1977 Exp $
 */
 #ifndef _SQLITE3_H_
 #define _SQLITE3_H_
@@ -1547,7 +1547,7 @@ struct sqlite3_module {
   int (*xDestroy)(sqlite3_vtab *pVTab);
   int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
   int (*xClose)(sqlite3_vtab_cursor*);
-  int (*xFilter)(sqlite3_vtab_cursor*, int idx,
+  int (*xFilter)(sqlite3_vtab_cursor*, char *zPlan, int nPlan,
                 int argc, sqlite3_value **argv);
   int (*xNext)(sqlite3_vtab_cursor*);
   int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
@@ -1626,7 +1626,10 @@ struct sqlite3_index_info {
     int argvIndex;           /* if >0, constraint is part of argv to xFilter */
     unsigned char omit;      /* Do not code a test for this constraint */
   } *const aConstraintUsage;
-  int idxNum;                /* Index number passed to xFilter */
+
+  char *zPlan;               /* xBestIndex blob passed to xFilter */
+  int nPlan;                 /* Size of nPlan */
+
   int orderByConsumed;       /* True if output is already ordered */
   double estimatedCost;      /* Estimated cost of using this index */
 };
@@ -1683,6 +1686,13 @@ struct sqlite3_vtab_cursor {
 int sqlite3_declare_vtab(sqlite3*, const char *zCreateTable);
 
 /*
+** This function is called by the xBestIndex method of a module to 
+** allocate space to store the query-plan passed to the corresponding
+** xFilter invocation(s).
+*/
+char *sqlite3_allocate_queryplan(sqlite3_index_info *, int);
+
+/*
 ** The interface to the virtual-table mechanism defined above (back up
 ** to a comment remarkably similar to this one) is currently considered
 ** to be experimental.  The interface might change in incompatible ways.
diff --git a/src/test8.c b/src/test8.c
index d95401ae5..5f005e03c 100644
--- a/src/test8.c
+++ b/src/test8.c
@@ -13,7 +13,7 @@
 ** is not included in the SQLite library.  It is used for automated
 ** testing of the SQLite library.
 **
-** $Id: test8.c,v 1.9 2006/06/13 14:16:59 danielk1977 Exp $
+** $Id: test8.c,v 1.10 2006/06/13 15:00:55 danielk1977 Exp $
 */
 #include "sqliteInt.h"
 #include "tcl.h"
@@ -344,21 +344,19 @@ static int echoRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){
 
 static int echoFilter(
   sqlite3_vtab_cursor *pVtabCursor, 
-  int idx,
+  char *zPlan, int nPlan,
   int argc, 
   sqlite3_value **argv
 ){
   int rc;
-  char zBuf[32];
   int ii;
 
   echo_cursor *pCur = (echo_cursor *)pVtabCursor;
   echo_vtab *pVtab = (echo_vtab *)pVtabCursor->pVtab;
   sqlite3 *db = pVtab->db;
 
-  sprintf(zBuf, "%d", idx);
   appendToEchoModule(pVtab->interp, "xFilter");
-  appendToEchoModule(pVtab->interp, zBuf);
+  appendToEchoModule(pVtab->interp, zPlan);
   for(ii=0; ii<argc; ii++){
     appendToEchoModule(pVtab->interp, sqlite3_value_text(argv[ii]));
   }
@@ -390,6 +388,8 @@ static int echoBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
   int ii;
   char *zWhere = 0;
   char *zOrder = 0;
+  char *zPlan = 0;
+  int nPlan = 0;
   int nArg = 0;
   echo_vtab *pVtab = (echo_vtab *)tab;
 
@@ -435,10 +435,22 @@ static int echoBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
   appendToEchoModule(pVtab->interp, zWhere);
   appendToEchoModule(pVtab->interp, zOrder);
 
+  nPlan = 2;
+  if( zWhere ){
+    nPlan += strlen(zWhere);
+  }
+  if( zOrder ){
+    nPlan += strlen(zWhere);
+  }
+  zPlan = sqlite3_allocate_queryplan(pIdxInfo, nPlan);
+  if( zPlan ){
+    sprintf(zPlan, "%s%s%s", 
+        zWhere?zWhere:"", (zOrder&&zWhere)?" ":"", zOrder?zOrder:"");
+  }
+
   sqliteFree(zWhere);
   sqliteFree(zOrder);
 
-  pIdxInfo->idxNum = 123;
   return SQLITE_OK;
 }
 
diff --git a/src/vdbe.c b/src/vdbe.c
index 26caf2edb..22967d41f 100644
--- a/src/vdbe.c
+++ b/src/vdbe.c
@@ -43,7 +43,7 @@
 ** in this file for details.  If in doubt, do not deviate from existing
 ** commenting and indentation practices when changing or adding code.
 **
-** $Id: vdbe.c,v 1.556 2006/06/13 14:16:59 danielk1977 Exp $
+** $Id: vdbe.c,v 1.557 2006/06/13 15:00:55 danielk1977 Exp $
 */
 #include "sqliteInt.h"
 #include "os.h"
@@ -4596,20 +4596,19 @@ case OP_VOpen: {
 ** P3 points to enough free space to use to marshall the arguments.
 **
 ** This opcode invokes the xFilter method on the virtual table specified
-** by P1.  The index number parameter to xFilter is the top of the stack.
+** by P1.  The query plan parameter to xFilter is the top of the stack.
 ** Next down on the stack is the argc parameter.  Beneath the
 ** next of stack are argc additional parameters which are passed to
 ** xFilter as argv. The topmost parameter (i.e. 3rd element popped from
 ** the stack) becomes argv[argc-1] when passed to xFilter.
 **
-** The index number, argc, and all argv stack values are popped from the
+** The query plan, argc, and all argv stack values are popped from the
 ** stack before this instruction completes.
 **
 ** A jump is made to P2 if the result set after filtering would be 
 ** empty.
 */
 case OP_VFilter: {
-  int iIndex;
   int nArg;
 
   const sqlite3_module *pModule;
@@ -4620,21 +4619,20 @@ case OP_VFilter: {
 
   /* Grab the index number and argc parameters off the top of the stack. */
   assert( (&pTos[-1])>=p->aStack );
-  assert( pTos[0].flags==MEM_Int && pTos[-1].flags==MEM_Int );
-  iIndex = pTos[0].i;
+  assert( pTos[0].flags&MEM_Blob && pTos[-1].flags==MEM_Int );
   nArg = pTos[-1].i;
 
   /* Invoke the xFilter method if one is defined. */
   if( pModule->xFilter ){
     int res;
     int ii;
-    Mem **apArg = pOp->p3;
+    Mem **apArg = (Mem **)pOp->p3;
     for(ii = 0; ii<nArg; ii++){
       apArg[ii] = &pTos[ii+1-2-nArg];
     }
 
     if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
-    res = pModule->xFilter(pCur->pVtabCursor, iIndex, nArg, apArg);
+    res = pModule->xFilter(pCur->pVtabCursor, pTos->z, pTos->n, nArg, apArg);
     if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
 
     if( res==0 ){
diff --git a/src/vtab.c b/src/vtab.c
index 8c8ba246d..f717831ff 100644
--- a/src/vtab.c
+++ b/src/vtab.c
@@ -11,7 +11,7 @@
 *************************************************************************
 ** This file contains code used to help implement virtual tables.
 **
-** $Id: vtab.c,v 1.6 2006/06/13 10:24:43 danielk1977 Exp $
+** $Id: vtab.c,v 1.7 2006/06/13 15:00:55 danielk1977 Exp $
 */
 #ifndef SQLITE_OMIT_VIRTUALTABLE
 #include "sqliteInt.h"
@@ -278,6 +278,17 @@ int sqlite3VtabCallConnect(Parse *pParse, Table *pTab){
 }
 
 /*
+** Resize pInfo->zPlan to nBytes bytes using realloc(). Set pInfo->nPlan
+** to nBytes and return a pointer to the allocated memory.
+*/
+char *sqlite3_allocate_queryplan(sqlite3_index_info *pInfo, int nBytes){
+  pInfo->nPlan = nBytes;
+  sqlite3ReallocOrFree(&pInfo->zPlan, nBytes);
+  return pInfo->zPlan;
+}
+
+
+/*
 ** This function is used to set the schema of a virtual table.  It is only
 ** valid to call this function from within the xCreate() or xConnect() of a
 ** virtual table module.
diff --git a/src/where.c b/src/where.c
index 2a047d5c1..99edb3f5c 100644
--- a/src/where.c
+++ b/src/where.c
@@ -16,7 +16,7 @@
 ** so is applicable.  Because this module is responsible for selecting
 ** indices, you might also think of this module as the "query optimizer".
 **
-** $Id: where.c,v 1.213 2006/06/13 14:16:59 danielk1977 Exp $
+** $Id: where.c,v 1.214 2006/06/13 15:00:55 danielk1977 Exp $
 */
 #include "sqliteInt.h"
 
@@ -1005,7 +1005,8 @@ static double bestVirtualIndex(
     pIdxCons->usable =  (pTerm->prereqRight & notReady)==0;
   }
   memset(pUsage, 0, sizeof(pUsage[0])*pIdxInfo->nConstraint);
-  pIdxInfo->idxNum = 0;
+  pIdxInfo->zPlan = 0;
+  pIdxInfo->nPlan = 0;
   pIdxInfo->orderByConsumed = 0;
   pIdxInfo->estimatedCost = SQLITE_BIG_DBL;
   nOrderBy = pIdxInfo->nOrderBy;
@@ -1468,6 +1469,9 @@ static void whereInfoFree(WhereInfo *pWInfo){
   if( pWInfo ){
     int i;
     for(i=0; i<pWInfo->nLevel; i++){
+      if( pWInfo->a[i].pIdxInfo ){
+        sqliteFree(pWInfo->a[i].pIdxInfo->zPlan);
+      }
       sqliteFree(pWInfo->a[i].pIdxInfo);
     }
     sqliteFree(pWInfo);
@@ -1754,8 +1758,8 @@ WhereInfo *sqlite3WhereBegin(
       }
 #ifndef SQLITE_OMIT_VIRTUALTABLE
       else if( pLevel->pIdxInfo ){
-        zMsg = sqlite3MPrintf("%z VIRTUAL TABLE INDEX %d",
-                    pLevel->pIdxInfo->idxNum);
+        zMsg = sqlite3MPrintf("%z VIRTUAL TABLE INDEX %s",
+                    pLevel->pIdxInfo->zPlan);
       }
 #endif
       if( pLevel->flags & WHERE_ORDERBY ){
@@ -1858,7 +1862,9 @@ WhereInfo *sqlite3WhereBegin(
         if( j==pIdxInfo->nConstraint ) break;
       }
       sqlite3VdbeAddOp(v, OP_Integer, i-1, 0);
-      sqlite3VdbeAddOp(v, OP_Integer, pIdxInfo->idxNum, 0);
+      sqlite3VdbeAddOp(v, OP_Blob, pIdxInfo->nPlan, 0);
+      sqlite3VdbeChangeP3(v, -1, pIdxInfo->zPlan, P3_DYNAMIC);
+      pIdxInfo->zPlan = 0;
       sqlite3VdbeAddOp(v, OP_VFilter, iCur, brk);
       zSpace = (char *)sqliteMalloc(sizeof(sqlite3_value*)*(i-1));
       sqlite3VdbeChangeP3(v, -1, zSpace, P3_DYNAMIC);